Tag Archives: Red-Breasted Merganser

Endangered Spring Migration It’s All About Timing

Endangered Spring Migration It’s All About Timing

Monday March 14 2011

Red-Breasted Merganser


Just as scientists are beginning to answer basic questions about migration, many migratory birds and other animals are in trouble

Are you starting to see some of your favorite birds come back from their wintering grounds? As the seasons change, many bird species come and go in the natural phenomenon of migration. Today, scientists are just beginning to answer some of the most basic questions about migration. But a shadow hangs over their research: Many migratory birds—and other migratory animals–are in trouble.


Waterfowl in danger

Spring Migration begins

Migration all year

What is migration? Many creatures wander, but only some are true migrants. Most biologists define migration as repeated seasonal movement between breeding and non-breeding grounds by the same individuals.

How far do birds migrate? Thanks to tracking devices, we now know the astounding distances that some migrating species travel. For sheer distance, nothing beats migrating birds. Sooty shearwaters astonished scientists by flying more than 40,000 miles in a loop from New Zealand to Chile, Japan, Alaska and California before a trans-Pacific trip back to New Zealand. The birds averaged more than 200 miles per day for 200 days.

Longest Known Non-stop Bird Flight: The real migration champ was a bar-tailed godwit that flew 6,340 miles nonstop between New Zealand and North Korea, where it rested briefly before continuing nearly a thousand additional miles to its breeding grounds in Alaska.


Migratory Birds

There are a range of techniques migrating birds use to navigate:

* Earth’s magnetic field: This was discovered by a series of experiments in the mid-1970s which reversed magnetic fields around songbirds, triggering them to fly the wrong direction. It is now known that some 50 species including birds follow magnetic pathways.
*Circadian clocks: innate temporal rhythms in the biochemical, physiological or behavioral processes of all living things, from plants to birds
*Internal compasses: Using the sun or stars as a compass to determine direction
*Smells: Some birds, including pigeons, use olfactory clues to find their way.
*Geographical features such as mountain ranges and coastlines. Most migrants seem to rely on a combination of these techniques depending on conditions.

Migratory bird
Some stay all year
First signs in north america

“The nonbreeding season drives a lot of what happens during rest of the annual cycle,” says Peter Marra, a research scientist at the Smithsonian Migratory Bird Center at the National Zoo. That cycle’s middle stages—the actual travel—remain terra incognita to scientists. The sheer number of habitats used at different points during migration presents a formidable challenge to conserving migratory birds.

The recently announced ICARUS Initiative will launch a satellite devoted to migratory animals and develop tiny, powerful transmitters that will allow researchers to follow creatures as small as insects across broad stretches of time and space.


The sights and sounds

*Habitat loss and degradation. The habitats of migratory species nearly everywhere are under pressure from deforestation, farming and expanding human populations. Human-made obstacles also hinder travel. In many cities, skyscrapers, for example, kill migratory songbirds.
* Global warming. Researchers are reporting new behaviors among migratory animals worldwide that may stem from changing climate—shifts in breeding ranges, mistiming of cues and departures, for example. “Since the wintering habitats are changing at different rates than more northerly habitats, things can get really of out sync,” says the Smithsonian’s Marra.

Out of whack: In the Netherlands, some populations of pied flycatcher have crashed because the birds are arriving from African wintering grounds too late to feast on a once predictable bounty of caterpillars. Higher springtime temperatures in Europe are causing the insects to hatch earlier than they once did.


Trumpeter and Tundra swan native species
Mute Swans adapt well

No one knows. Recently, some birds have shown flexibility by changing routes or timing or breeding sites in response to new environmental conditions. In the Midwest, for instance, ducks are arriving later in the fall and resting longer before continuing south, perhaps in response to higher temperatures.

Along the east coast of Massachusetts, where temperatures are rising and the insects on which birds feed on hatching sooner, 8 of 32 migratory songbirds looked at have begun arriving earlier from their wintering grounds—primarily species that winter in the southern United States as opposed to farther away in the Tropics.

“But I think it would be dangerous to assume that all species can adapt,” says Princeton University ecologist David Wilcove. As Wilcove writes in his book No Way Home: The Decline of the World’s Great Animal Migrations, “The irony is that just as the phenomenon of migration is slipping away, we are entering a golden age for studying it.”

Spring Migration: It’s All About Timing

Timing and luck

From January to June, each migratory species has its own special time to return to summer breeding grounds
Somewhere in North America, there is probably some kind of migratory movement of birds every day. But spring migration—the mass movement of birds toward their breeding grounds—happens with predictable timing each year. The precise local timing varies, of course, with latitude and elevation. “Early spring” might mean early February in the southernmost states, late March or early April in the north, or even May in the far north and high mountains.

Mass Migrations

Among the first groups of birds to move north are waterfowl: ducks, geese, and swans may begin migrating as soon as frozen lakes and marshes start to thaw. Even in the northern Provinces, flocks of waterfowl may arrive in late February. Also on the move this early are some species that migrate mostly within North America, spending the winter as far north as they can. They include killdeer and red-winged blackbirds.

Some birds of prey also start to migrate in early spring. Bald eagles, rough-legged hawks and red-shouldered hawks are actively moving north even while wintry conditions still prevail.

Other surprisingly early migrants include purple martins, returning from South America and reaching Florida and Texas by late January and making it to northern states by the end of March.

Blue heron nesting zone

Many native sparrows tend to be early migrants, with large numbers moving in southern states in March and in northern states by early April. Kinglets and sapsuckers are in this moderately early wave as well. And most blackbirds move north during the first half of the spring.


Shorebirds (sandpipers, plovers and their relatives) have a protracted migration, with some species represented among the earliest and latest migrants. Pectoral sandpipers and American golden-plovers, wintering in South America, come back to southern provinces by the end of February and reach northern provinces by March. Many other species migrate later, with peak passage in most areas during April and May. Long-distance migrants that winter in southern South America, white-rumped sandpipers peak in  central Canada and  United States in late May or early June.

Southern Ontario


The great northward flood of songbirds that have wintered in the tropics—including warblers, tanagers, buntings, grosbeaks, orioles, vireos and thrushes—occurs primarily during April and May, filling North American woodlands with color, song and activity. For many birders, warblers are particular favorites; there are several places in the country where you can see more than 30 species of these tiny, colorful gems during the course of the season.

Deer Migration Huge

By early June, aside from a few shorebirds and straggling songbirds, spring migration is over across most of North America. This is when birders turn their attention to local nesting species—and get ready to watch for the first of the fall migrants, which in some areas start showing up by early July.

New Born signet
Mute swan
Refections of spring

Sources: National Wildlife Foundation, Wikipedia


Doug Worrall Photography

The Red-Breasted Merganser Hamilton

The Red-Breasted Merganser Hamilton

Mersenger ducks

(Mergus serrator)

Wednesday November 16 2010

The red-breasted merganser is a medium-sized “saw-bill” sea duck. An adult weighs 800–1,350 grams (1.7–3.0 lbs) and is 51–64 cm (20.0–25.1 in.) long. Males are larger than females. Both sexes have a long narrow red bill with a black tip, red-orange feet, and black wings with white patches across the inner wing. Their serrated bill is highly specialized for grasping small fish securely

DescriptionThe red-breasted merganser is a medium-sized “saw-bill” sea duck. An adult weighs 800–1,350 grams (1.7–3.0 lbs) and is 51–64 cm (20.0–25.1 in.) long. Males are larger than females. Both sexes have a long narrow red bill with a black tip, red-orange feet, and black wings with white patches across the inner wing. Their serrated bill is highly specialized for grasping small fish securely

Diving ducks

Adult males have a head that is dark metallic green in the face with black elsewhere. Elongated feathers at the rear of the head form a long, shaggy, and double-pointed crest. Males have a white neck ring with varied body colors that include speckled brown chest, and gray sides and flanks. In late summer during molt, males resemble breeding females, except white on inner forewing is more extensive in male.

Adult females are largely gray-brown with white on chin, throat, breast, and belly; they retain this plumage year-round.

Horned Greb Duck


Red-breasted mergansers occur in arctic and subarctic regions throughout the northern hemisphere. In North America, they breed across the continent from the Aleutian Islands and Alaska, east across the Canadian arctic to the Atlantic provinces, Great Lakes region, and northeastern states.Below a Mallard duck that Winters in Hamilton.

Mallard duck

Red-breasted mergansers winter along the entire coastline of North America, in the Pacific from the Aleutian Islands of Alaska to Baja California and in the Atlantic from Nova Scotia to northern Mexico. They are found mostly on coastal bays, large calm, open-water areas, estuaries, and harbors. They also winter on large interior lakes, such as the Great Lakes and the Great Salt Lake in Utah.

Red-breasted mergansers are more frequently found in salt water than common mergansers, which winter more on fresh water. The large distance between arctic breeding areas and wintering areas as far south as coastal Mexico suggests a strong migratory tendency and dispersal ability. However, nothing is known about migration patterns or connectivity between nesting and wintering grounds.

Migrating duck

Habitat and Habits

Red-breasted mergansers are thought to establish pair bonds in winter. They are late spring migrants, flying in pairs or flocks of 5–15 individuals along major rivers, lake chains, and coastlines during day and overland by night. They also breed later than most ducks, beginning nesting in mid-June in Alaska, and from late May to early July in Atlantic Canada.

They breed at higher latitudes where tundra and boreal forest predominate. On tundra, they prefer larger, deeper lakes rather than small ponds. Most individuals breeding in the interior of North America migrate to and along the Pacific or Atlantic coasts before reaching final winter destinations.

Females return to the same nesting area each year. They nest on the ground, primarily near the coast, rivers, or large bodies of water. Crevices in coastal rocky cliffs and islets are also used for nesting. They often nest in loose colonies, sometimes 


in association with terns, gulls, or eiders.




The nest is a shallow bowl, often with a roof of standing vegetation, lined with increasing amounts of grass and downy feathers from the female as incubation progresses. Females lay an average of 9-10 eggs, but clutch size can range between 5–24 eggs. It is not uncommon for more than one female to lay eggs in another’s nest. Eggs are incubated approximately 30 days, and females may renest if the first nest is lost to predators.

Young from several broods may join to form large aggregations called crèches, which are typically attended by only one female. Young are often abandoned by the female before they can fly, often within the first week after hatching. Time required to reach fledging is poorly known, but assumed to be 60–65 days.

Males remain near the nest site until females begin incubating, then depart for molting locations, where they become flightless for 3-4 weeks while they grow new wing feathers.It is unknown where specific populations go to molt. Females molt with or near their broods on nesting areas.

Information Ducks unlimited


Doug Worrall